Serial Advanced Technology Attachment. A computer bus designed to transfer
data to and from a hard drive using serial signaling technology. Because
SATA cables are thinner than its ribbon type counterpart, they can be
connected to more devices while maintaining its signal integrity.
Basically, a scalable system or system architecture is one that can be
modified in its size or
configuration to suit changing conditions. As an example, a company that is
set up to run a client/server type network may only have 10 people currently
set up on the network, but the company plans to have many more set up in the
coming years. In this instance, they would need to be able to make this
A process that calculates numbers in sequence.
In computer programming, this would refer to a specific identifying
enclosing context. Each programming language uses various types of scopes to
accomplish different things.
- Screen Flicker:
This is generally referring to the flickering of a display screen and can be
caused by a number of factors, the most important of which is the
monitor's refresh rate, or the speed that the screen is re-drawn. If the
refresh rate is too slow, the screen will appear to glimmer. Another factor
that affects screen flicker is the persistence of the screen phosphors.
Low-persistence phosphors fade more quickly than high-persistence monitors,
making screen flicker more likely. Screen flicker can also be affected by
lighting. Finally, screen flicker is a subjective perception that affects
people differently. Some people perceive screen flicker where others do not.
Most people perceive no screen flicker if the refresh rate is 72 MHz or
Abbreviation of "Small Computer System Interface". It is pronounced "scuzzy,"
and is a parallel interface standard used by Apple Macintosh computers, PCs, and
many UNIX systems for the purpose of attaching peripheral devices to computer
systems. Nearly all
Apple Macintosh computers, excluding only the earliest Macs and the recent
iMac, come with a SCSI port for attaching devices such as disk drives and
SCSI interfaces provide for faster data transmission rates (up to 80
megabytes per second) than standard serial and parallel ports. In addition,
you can attach many devices to a single SCSI port, so that SCSI is really an
I/O bus rather than simply an interface.
The following varieties of SCSI are currently implemented:
SCSI-1: Uses an 8-bit bus, and supports data rates of 4 MBps
SCSI-2: Same as SCSI-1, but uses a 50-pin connector instead of a 25-pin
connector, and supports multiple devices. This is what most people mean when
they refer to plain SCSI.
Wide SCSI: Uses a wider cable (168 cable lines to 68 pins) to support 16-bit
Fast SCSI: Uses an 8-bit bus, but doubles the clock rate to support data
rates of 10 MBps.
Fast Wide SCSI: Uses a 16-bit bus and supports data rates of 20 MBps.
Ultra SCSI: Uses an 8-bit bus, and supports data rates of 20 MBps.
SCSI-3: Uses a 16-bit bus and supports data rates of 40 MBps. Also called
Ultra Wide SCSI.
Ultra2 SCSI: Uses an 8-bit bus and supports data rates of 40 MBps.
Wide Ultra2 SCSI: Uses a 16-bit bus and supports data rates of 80 MBps.
Synchronous Digital Hierarchy. A method used for multiplexing many circuits
with a low bit rate onto fewer circuits with a higher bit rate, and
vice-versa (de-multiplexing). Used primarily in the telecomms industry to
carry telephony traffic. This network can also be used to carry IP traffic.
Short for "Synchronous Dynamic Random Access Memory". This is a newer type of DRAM that
has the ability to run at much higher clock speeds than conventional memory. SDRAM actually
synchronizes itself with the CPU's bus and is capable of running at 100 MHz,
about three times faster than conventional FPM RAM, and about twice as fast
EDO DRAM and BEDO DRAM. SDRAM is replacing EDO DRAM in many newer computers.
Today's fastest Pentium systems use CPU buses running at 100 MHz, so SDRAM
can keep up with them, though barely. Future PCs, however, are expected to
have CPU buses running at 200 MHz or faster. SDRAM is not expected to
support these high speeds which is why new memory technologies, such as
RDRAM and SLDRAM, are being developed.
Also referred to as "Level 2 cache" or "L2". In general, L2 cache memory resides on a separate
external chip from the microprocessor chip. However, The Pentium
Pro processor has an L2 cache on the same chip as the microprocessor.
A relationship between words, phrases or any other allowable constraint and
their actual meaning. This is contrast to "Syntax". An example could be; if
you enter a misspelled command, it would be a syntax error, but if you enter
what may be a legitimate command but is not understood in its current
context, this would be a "semantics error".
This refers to a material that is not a good conductor of electricity
(copper) nor a good insulator (plastic). Silicon and germanium are the most
common semiconductor materials.
Semiconductor materials are used in computer chips, both for CPU and memory.
Its purpose is to create miniature electronic components that take up less
space and require less energy.
(Search Engine Optimization) SEO is a process of arranging a web site's
content to obtain high rankings in various search engines (both the site and
individual pages), and includes tailoring on-page text (such as headlines
and subtitles) as well as choosing the proper keywords for a page's meta
A sequence of commands that execute orders in a database.
- Serial Port:
A port, or interface, that can be used for serial communication, in which
only 1 bit is transmitted at a time. Most serial ports on personal computers
conform to the RS-232C or RS-422 standards. A serial port is a
general-purpose interface that can be used for almost any type of device,
including modems, mice, and printers (although most printers are connected
to a parallel port).
This is a mainframe computer that serves the other computers attached to it.
Abbreviation of "Synchronous Graphic Random Access Memory". This is a type
of DRAM used commonly on graphics accelerators and video adapters. Like SDRAM,
SGRAM can synchronize itself with the CPU bus clock up to speeds of 100 MHz.
A technique used to increase a computer's speed by using high-speed RAM
memory in place of slower ROM memory (RAM is about three times as fast as
ROM). On PCs, for example, all code to control hardware devices, such as
keyboards, is normally executed in a special ROM chip called the BIOS ROM.
However, this chip is slower than the general-purpose RAM that comprises
main memory. Many PC manufacturers, therefore, configure their PCs to copy
the BIOS code into RAM when the computer boots. The RAM used to hold the
BIOS code is called shadow RAM.
Software distributed on the basis of an honor system. Most shareware is
delivered free of charge, but the author usually requests that you pay a
small fee if you like the program and use it regularly. By sending the small
fee, you become registered with the producer so that you can receive service
assistance and updates. You can copy shareware and pass it along to friends
and colleagues, but they too are expected to pay a fee if they use the
Shareware is inexpensive because it is usually produced by a single
programmer and is offered directly to customers. Thus, there are practically
no packaging or advertising expenses.
- Sheet Tab:
In spreadsheet applications, this would refer to a tab at the bottom of a
work sheet that acts as a means to identify or access different sheets
within a workbook.
Just like the shell of an egg is the outermost layer, in computer
technology, this refers to the outermost layer of a program. Operating systems and applications sometimes provide an alternative shell to
make interaction with the program easier. For example, if the application is
usually command driven, the shell might be a menu-driven system that
translates the user's selections into the appropriate commands.
Sometimes called command shell, a shell is the command processor interface.
The command processor is the program that executes operating system
commands. The shell, therefore, is the part of the command processor that
accepts commands. After verifying that the commands are valid, the shell
sends them to another part of the command processor to be executed.
- SID (Service
Used in the DOCSIS standard to defines a particular mapping between a cable
modem (CM) and the CMTS. The SID is used for the purpose of upstream
bandwidth allocation and class-of-service management.
Acronym for single in-line memory module, a small circuit board that can
hold a group of memory chips. Typically, SIMMs hold up 8 (on Macintoshes) or
9 (on PCs) RAM chips. On PCs, the ninth chip is often used for parity error
checking. Unlike memory chips, SIMMs are measured in bytes rather than bits.
SIMMs are easier to install than individual memory chips.
The bus from a SIMM to the actual memory chips is 32 bits wide. A newer
technology, called dual in-line memory module (DIMM), provides a 64-bit bus.
For modern Pentium microprocessors that have a 64-bit bus, you must use
either DIMMs or pairs of SIMMs.
A one directional communications circuit that can only either transmit or
receive, but not both. Two good examples of simplex devices would be your TV
or an FM radio.
Abbreviation of single in-line package, a type of housing for electronic
components in which the connecting pins protrude from one side. Compare with
DIP and PGA. A SIP is also called a Single In-line Pin Package (SIPP).
This is a peer-to-peer voice over Internet protocol (VoIP). This Internet
telephony network was created by the same people that created Kazaa (Niklas
Zennström and Janus Friis). It was developed as a free desktop software
application that gives users the ability to make free Internet phone calls
to other Skype users or you can use the application to place and receive
phone calls to and from traditional phone lines for a reduced fee.
Stands for Serial Line Interface Protocol. This is another application that
allows for a connection to another computer.
- SMS (Short
A popular wireless service that is used for sending and receiving short
messages up to a maximum of 160 characters. The service is used for text
messaging between cell phones that are on a GSM (Global System for Mobile)
Stands for Simple Mail Transfer Protocol.
Stands for "Simple Network Management Protocol". It was developed in 1988
become a standard for Internet work management and used almost exclusively
in TCP/IP networks.
In computer technology, a Socket refers to a receptacle that provides a
means of communication between two processes.
- Socket 7:
Socket 7 is a connection format used on older processors such as the Cyrix
M2, AMD K6 and K6-2.
- Socket 8:
The Socket 8 connection format was exclusively used on Intel Pentium Pro and
Pentium II OverDrive processors.
- SODIMM (Small
Outline Dual Inline Memory Module):
These memory modules are typically used in laptop and notebook computers
where space and low power consumption is a major consideration. SODIMM's are
about half the size of its DIMM counterpart.
- Software Modem:
A modem implemented entirely in software. Software modems rely on the
computer's processor to modulate and demodulate signals.
- Source Code:
Computer programs or operating systems are originally written by a human
being in a programming language. This is called the source code of the
software. To be actually used by a computer, the program has to be
translated by the computer from the source code into the machine language
that the computer understands and can execute. This translation process is
referred to as compiling.
This is a program, the actual code the computer reads. All other stuff is
hardware. A floppy disc is hardware.
This is to transmit unwanted messages, usually over email, to a great many
To fool. In networking, the term is used to describe a variety of ways in
which hardware and software can be fooled. Email spoofing, for example,
involves trickery that makes a message appear as if it came from a
legitimate business email address.
The process of storing a device (eg: printer) output signal in a queue,
while the device can take on other actions. When the device is ready to take
on other actions, it will draw from the queue.
The term spooling is derived from the acronym "Spool": Simultaneous
Peripheral Operations On-Line
(Structured Query Language) A specialized programming language for sending
queries to databases. Most industrial-strength and many smaller database
applications can be addressed using SQL. Each specific application will have
its own version of SQL implementing features unique to that application, but
all SQL-capable database support a common subset of SQL.
Short for static random access memory, and pronounced ess-ram. SRAM is a
type of memory that is faster and more reliable than the more common DRAM
(dynamic RAM). The term static is derived from the fact that it doesn't need
to be refreshed like dynamic RAM.
While DRAM supports access times of about 60 nanoseconds, SRAM can give
access times as low as 10 nanoseconds. In addition, its cycle time is much
shorter than that of DRAM because it does not need to pause between
accesses. Unfortunately, it is also much more expensive to produce than
DRAM. Due to its high cost, SRAM is often used only as a memory cache.
- SSL: (Secure
A protocol designed by Netscape Communications to enable encrypted,
authenticated communications across the Internet. SSL is used mostly in
communications between Web browsers and Web servers. URLs that begin with
"https" indicate that an SSL connection will be used.
As a web site term, this is used to describe a web page that is not
interactive. The webmaster writes information to the source code of a web
page and can only be changed by re-writing the source code. A visitor to the
web page cannot manipulate its contents.
This refers to a method of concealing data inside of data. The secret
information can be hidden inside of an image or sound file so that a normal
user would not know that it existed.
A technology that involves the playing of audio or video files in real time
over the Internet.
A procedure that performs a specific function; usually a process that may be
needed several times or a routine that may be used in several different
programs. For example, many subroutines have been created to parse
- Subscriber Unit
An alternate term for cable modem.
A memory management technology in Windows Vista that is designed to launch
applications more quickly by getting the most out of the available RAM
(random access memory). SuperFetch has the ability to learn which
applications you use most often so that it can pre-load them into memory.
Stands for Super Video Graphics Adapter. It's a high level monitor.
- Swap File:
A swap file is an area on your hard disk used as virtual memory. It's called
a swap file because virtual memory management software swaps data between it
and main memory (RAM).
In the Windows Operating System, a temporary swap file can be configured
only when the system needs it. In a Linux and Unix environment, permanent
swap files are used which dedicate a certain portion of hard drive space.
- Swap Space:
Disk space used by the kernel as “virtual” RAM. It is slower than RAM, but
because disk space is cheaper, swap is usually more plentiful. Swap space is
useful to the kernel for holding lesser-used data and as a fallback when
physical RAM is exhausted.
In networks, a device that filters and forwards packets between LAN
segments. Switches operate at the data link layer (layer 2) of the OSI
Reference Model and therefore support any packet protocol. LANs that use
switches to join segments are called switched LANs or, in the case of
Ethernet networks, switched Ethernet LANs.
A small lever or button. The switches on the back of printers and on
expansion boards are called DIP switches. A switch that has just two
positions is called a toggle switch.
Another word for option or parameter -- a symbol that you add to a command
to modify the command's behavior.
- Switching Hub:
A high-performance hub, also called a "switching hub" that can recall what
devices are connected to each port and transfer necessary data to the
required port. Unlike the conventional hub, which sends data to every port.
Refers to two or more elements, events or operations programmed to occur at
a predefined moment in time or place.
Synchronous can refer to: (1) A communications method that transmits a group
of characters as a block of data rather than as individual characters. (2) A
reference to the fact that two different data streams are tied, or
synchronized, to a single reference clock. (3) Data transmitted in a
Grammatical structuring of data using a special code that defines how this
special code is used to form words, phrases or any other allowable
A combination of the hardware, software, and firmware. A system typically
consists of components (or elements) which are connected together in order
to accomplish a specific function or set of functions.